He had an unfree program (the wattcp library) and GNU tar and
discovered that he wasn't allowed to ship a program that linked
these two together. He then said, gloriously, "please don't try
to say the problem was cause by those other licenses -
they did not prevent anyone else from getting copies..." :-)
OK Les, I promise not to say it. However...

I'm not sure what you are trying to imply here. I could redistribute
copies of the other two components - but that's irrelevant since anyone
could get them in source anyway (they were only unfree in the reverse
way that the GPL redefines free to mean restricted).

Err, one library according to you, was unfree in the sense that you weren't
allowed to change it in any way; to enhance it, or to fix bugs.

That's not an accurate description, although it did have a restriction
on distributing modified versions. I could, of course, change my own
copy and submit bug fixes and enhancements to the author for
incorporation - or make the source modifications available separately
from the package. The restriction was more about preventing broken
versions from being distributed than enhancements.

I could have
redistributed the combination if I had started with the original pdtar
instead of gnutar.

You could, but if what you said was true, you still wouldn't be able to
fix bugs in one of the libraries. And if, to you, free software is that
which is free (as in beer) but you aren't allowed to fix bugs, then
you're welcome to it.

The best way to fix bugs is to get the fix incorporated in the base
package so it can be properly tested, merged with other fixes, and
provided to everyone using it. Otherwise you can s/fix/add/ in your
description of what you want to be permitted to do followed by
distributing them in a package someone else tries to support. How many
broken TCP stacks do we really want on our networks where someone thinks
cranking the retry timer gives it an advantage? There is the argument
that if the author/maintainer stops updating, the package can die.
Well, these were DOS libraries. The sooner that stuff died the better.
Knowledge about TCP didn't start or end with that package and copies
are probably still available in archives somewhere.